I am a Canon professional photographer (Sports). I have used Canon 1D, 1D Mark II, 1D Mark III, 1D Mark IV, EOS 5D and 7D. I have yet to see a problem with the front and back focusing.

I attended a seminar given by Canon technical representatives and technicians from Japan. They shows us how they match lenses to camera bodies and vice versa. They showed us how they calibrate each lens to the body in question and I even tested it out.

All I can say is the problem is more than likely from the photographer. They are looking at things too deeply and not focusing in on their mistakes. They are making some kind of mistake but blaming Canon. My fellow Canon professional photographers also never had issues pertaining to front/back focusing.

Todays cameras are so sophisticated that you are liable to hit a function button and not know it. We did discover several issues pertaining to a few "L" lenses but these were rectified before it hit the market. We were given demo "L" lenses to shoot with and we found the rear element in this lens was not aligned properly but those lenses never even reached the warehouse before they were repaired!

In this case I don't see why Canon or Nikon etc ever included an AF fine tuning facility in their cameras .. there are so many "non Canon-professional photographers" out there who are having real-life problems with there bodies and lenses and no Canon technical reps from Japan to help !!